1. Field of the Invention
This invention relates to an article-detect signal generating network for a sorting apparatus, and in particular, to a network adapted to separate an article-detect signal generated by two randomly disposed, next-abutting articles so as to denote the presence of two separate articles.
2. Description of the Prior Art
A sorting apparatus adapted to classify articles disposed randomly within a viewing zone typically includes a viewer for viewing the zone in which the articles are disposed. Such sorting apparatus is responsive to the light reflected from the articles within the viewing zone to generate characteristic signals representative of a predetermined physical characteristic of each article. For example, it is known that all organic matter reflects light in the infrared range. Thus, an electrical characteristic signal representative of reflected infrared light would contain information regarding the presence and location of an article within the viewing zone.
In apparatus adapted to classify an array of randomly disposed articles, signals indicative of the presence and location of articles within the viewing zone assume a critical importance. For unlike the situation extant in apparatus adapted to sort highly predictable, channelized arrays of articles, there is no guarantee in a random sorting apparatus that an article will occupy a given position within the viewing zone. It is now typical practice to generate "article-detect" signals in such random sorting apparatus by a comparison of the characteristic signal representative of light reflected from articles with some predetermined reference level. So long as the characteristic signal exceeds the reference level (selected so as to avoid extraneous reflections from triggering the classification circuitry), an "article-detect" signal is generated.
Complications arise, however, when consideration is given to the case wherein two (or more) articles happen to randomly abut one against the other in the viewing zone. In this instance, it is necessary to provide some mechanism whereby the classification circuitry is made aware of the presence of the two (or more) distinct articles. It is an object of this invention to provide circuit arrangement adapted to separate the article-detect signals produced by two (or more) separate but next-abutting articles to indicate to the classification circuitry the presence of two (or more) different articles.